New York (CNN Business) — Volatility is back. It's a shock for stock market investors who have enjoyed predictable returns over the past decade. In seven of the past nine years, the S&P has boasted double-digit returns. In 2017, the S&P 500 returned 22%.

LONDON (Reuters) - Recent sharp selloffs across global financial markets are probably the first of many, as investors adjust to a world of tighter monetary conditions and the threat of economic downturn, the Bank of International Settlements said on Sunday.

Wall Street’s main indexes fell more than 2 percent on Friday in a broad sell-off led by declines in big Internet and technology shares, and posted their largest weekly percentage drops since March as concerns over U.S.-China trade tensions and interest rates convulsed Wall Street.